64-bit container case

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on December 10, 2010 17:57:41_

PR 408518

filing a container case to cover 64-bit porting of Dr. Memory.
the major task is re-designing the shadow memory structure and
rewriting all of the hand-coded machine instruction sequences for
accessing shadow memory. we'll need more indirection with
some kind of page-table-style structure, and may end up needing
caches to achieve good performance: much more complex than 32-bit.

xref PR 575713

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=111_